1. Field of the Invention
The present invention relates to a multilayer semiconductor integrated circuit, and more particularly to the transfer of signal between adjacent layers of the multilayer semiconductor integrated circuit.
2. Description of the Prior Art
FIG. 3 is a sectional view showing a part of a conventional multilayer semiconductor integtrated circuit.
Referring to FIG. 3, electronic circuit regions 1 and 2 are formed to be stacked in three-dimensions through individual insulating regions 3 to 5.
The electronic circuit region 1, for example, consists of p-type semiconductor regions 6 and 7, an n-type semiconductor region 8, a gate region 9 made of polysilicon, and wiring regions 10 and 11 made of metal material. The electronic circuit region is formed on the insulating region 3 made of SiO.sub.2 and covered with the insulating region 4 made of SiO.sub.2.
The electronic circuit region 2, for example, consists of n-type semiconductor regions 12 and 13, a p-type semiconductor region 14, a gate region 15 made of polysilicon, and wiring regions 16 and 17 made of metal material. The electronic circuit region 2 is formed on the insulating region 4 and covered with the insulating region 5 made of SiO.sub.2.
The electronic circuit region and 2 are electrically connected with each other through a conductive path 18 which is formed by making a through hole in the insulating regions 4 and 5 and thereafter embedding metal material in the through hole.
According to the multilayer semiconductor integrated circuit, the p-type semiconductor region 8 of the electronic circuit region 1 formed at a lower layer part is electrically connected with the n-type semiconductor region 13 of the electronic circuit region 2 formed at an upper layer part through the wiring regions 10 and 17 and the conductive path 18, which eventually makes it possible to transfer a signal through the conductive path 18 from the electronic circuit region 1 to the electronic circuit region 2 or vice versa.
FIG. 4 is a sectional view showing a part of another conventional multilayer integrated circuit.
Referring to FIG. 4, an electronic circuit region 2 formed at an upper layer part has p-type semiconduotor regions 19 and 20 and n-type semiconductor regions 21 and 22 for forming a thyristor, instead of the semiconductor regions 12 to 14 for forming a p-channel MOS transistor of FIG. 3. And a p-type semiconductor region 6 of an electronic circuit region 1 formed at a lower layer part is electrically connected with the p-type semiconductor region 19 of the electronic circuit region 2 through a p-type columnar semiconductor region 23. Other reference numerals than the above-mentioned designate the same parts as in FIG. 3.
According to the multilayer semiconductor integrated circuit, a signal can be transferred through the columnar semiconductor region 23 from the electronic circuit region 1 to the electronic circuit region 2 or vice versa.
The conventional multilayer semiconductor integrated circuits, however, transfer the signal between the upper layer part and the lower layer part only through the conductive path 18 by the through hole or the columnar semiconductor region 23, and therefore the conductive path 18 and the columnar semiconductor region 23 merely function as passive elements, which eventually makes a space in a semiconductor chip useless.